April 15, 1886J 



NA rURE 



575 



of mercury between 0° and - 39° C, by Profs. W. E. Ayrton 

 and John Terry. On November 14, 1885, Mr. G. M. Whipple 

 gave the Socieiy the resiiUs of the examination of thermometers 

 down to the mehing-point of mercury. There was, however, 

 no evidence as to whether the contraction of the mercury con- 

 tinued uniform, as the thermometers were only compared witli 

 mercurial ones. The authors have therefore examined this 

 jjoint, and have made a series of comparisons of a mercurial 

 thermometer, lent them by Mr. Whipple, with a constant volume 

 air-thermometer, both immersed in a bath of frozen mercury, 

 which was allowed to gradually become warm. The result ob- 

 tained was that no certain deviation from a linear law c .uld 

 be detected in the expansion of jrercury when temperature was 

 measured by the increase of pressure required to keep a volume 

 of air constant. Hence temperatures down to — 39° C. may be 

 correctly measured by a mercury thermometer the stem of which 

 is graduated for equal volumes. — On the expansion produced by 

 amalgamation, by Profs. W. E. Ayrton and John Perry. It has 

 been accidentally observed by the authors that the amalgamation 

 of brass is accompanied by gr?at expansive force. If one edge 

 of a str.aight thick brass bar be amalgamated, ii will be found 

 that in a short time the bar is curved, the amalgamated edge 

 being always convex, and the opposite concave. The authors 

 imagine that a similar action may be the primary cause of the 

 phenomena presented by the Japanese " magic mirrors." 

 Japanese mirrors are made of bronze, and have a pattern cast 

 upon the back, and although to the eye no trace of it can be dis- 

 covered upon the polished reflecting surface, yet, when light is 

 reflected by certain of these mirrors on to a screen, the pattern is 

 distinctly visible in the luminous patch formed. In a paper 

 before the Royal Society they have shown that this is due to the 

 polished side opposite the thinner parts of the casting being 

 more convex than the others, a conclusion verified by the fact 

 that the pattern is reversed when formed by a convergent beam 

 of light. Such a condition of things would evidently result 

 from a uniform expansive stress taking place over the reflecting 

 surface, the thinner, and consequently ihe weaker, parts becom- 

 ing more convex or less concave than the others. The authors 

 have hitherto attributed this inetju-ility of curvature to a 

 mechanical distortion to which the mirrors are intentionally sub- 

 mitted during manufacture, to produce the general convexity of 

 the polished surface, but they now think it possible that the use 

 of a mercury amalgam in the process of poli-hing may have an 

 effect in the production of this inequality of curvature. 



Victoria (Philosophical) Institute, April 5. — A paper by 

 Mr. W. P. James, F. L. S. , giving a careful risumi of the 

 various records of the Creation current among nations in ancient 

 and modern times, was read. 



Institution of Civil Engineers, April 6. — Sir Frederick 

 Bramwell, F.R.S., President, in the chair. — The paper read 

 was on water-purification : its biological and chemical basis, 

 by Percy F. Frankland, Ph.D. 



Dublin 

 Royal Society, February 17. — Physical, Experimental, and 

 Applied Science Sections. — Prof. W. F. Barrett in the chair. — 

 Prof. E. Hull, LL.D., F.R.S., read a paper on the difl'erent 

 varieties of Irish paving sets. The use of Irish paving mate- 

 rials is of comparatively recent date, North Wales having been 

 the chief source of supply. Granite, which affords compara- 

 tively tough paving sets, capable of preserving a rough sur- 

 face, is worked at Bessbrook, Goraghvvood, and Castlewellan. 

 Whinstone, similar to that of Penmaen nawr in Wales, and 

 from rocks of the same group, is worked at Ballintoy, Co. 

 Antrim, and Arklow, Co, Wicklow. The author expressed the 

 opinion that sets of the granitoid class were most serviceable in 

 those parts of a city where the traffic was of an ordinary charac- 

 ter, but where it was excessive in quantity and weight paving- 

 stones of the whinstone class, especially if largely crystalline, were 

 preferable. — On a sine and tangent galvanometer, by Prof. G. 

 F. Fitzgerald, F. R.S. — An improved method for determining 

 the specific gravity of solids,by R. J. Moss, F.C.S. This is an 

 application of Sprengel's specific-gravity tube to solids. The tube 

 employed consists of two parts fitting together by an accurately- 

 ground joint the full width of the tube. The error arising from 

 this joint may easily be reduced to one-tenth of a milligramme. 

 With a tube of I cubic centimetre capacity, about 2 grammes 

 of most minerals can be employed. If benzene or turpentine 

 be used instead of water, no difficulty arises with air-bubbles. 



Results sufficiently accurate for determinative purposes can be 

 obtained with even 20 milligrammes of the solid body. 



Natural Science Section.— Prof. J. P. O'Reilly, C.E., in the 

 chair. — On some recent discoveries in the salt-range, Punjab, 

 by Mr. A. B. Wynne. Certain peculiarities of the section at 

 different parts of the range were described, and attention was 

 called to the absence of any recognisable Devonian formation 

 in the neighbouring parts of the country, as well as in the 

 salt-range itself, which added interest to the recent discovery by 

 Dr. H. Warth of fossils believed to be of Devonian age, occur- 

 ring as rolled and derived or transported inclusions of some of 

 the liter Jurassic or Cretaceous conglomerates. Specimens of 

 these fossds were exhibited ; the most characteristic is Conularia. 

 It was suggested as probable that the parent beds lay to the 

 southward. Other cases of derivative fragments amongst the 

 Salt-Range series having an equally obscure origin were men- 

 tioned, all p:)inting to a lost land, perhaps buried under the 

 deserts and alluvial tracts stretching away into Sind. — On the 

 relationship of the structure of rocks to the conditions of their 

 formation, by II. J. Johnston-Lavis, M.D. Communicated by 

 Rev. Dr. S. Haughton, F.R.S. 



Edinburgh 

 Mathematical Society, April 9. — Dr. R. M. Ferguson, 

 President, in the chair. — Mr. J. .S. Mackay communicated a 

 note on the divisibility of certain numbers. — Mr. R. E. Allardice 

 discussed the projective geometry of the sphere. — Mr. John 

 Alison gave statical proofs of several geometrical theorems. 



Paris 

 Academy of Sciences, April J. — M. Jurien de la Graviere, 

 President, in the chair. — Obituary notice of M. A. Lallemand, 

 Member of the Section for Physics, by M. Mascart.— On the 

 constitution of the earth's crust (concluded), by M. Faye. The 

 author concludes that the revolutions of the globe are due, not 

 to contraction caused by a general and uniform chilling process, 

 as hitherto supposed, but to the circumstance, peculiar to the 

 earth, that this chilling process goes on at an accelerated rate 

 and more deeply under the marine basins than under the 

 continents. — On the magnetic perturbation observed throughout 

 France on March 30, by M. Mascart. The disturbance, which 

 began about 8.^30 a.m., lasted for over two days, gradually dying 

 out on April I. — Summary remarks on the fauna of Tonquin, by 

 M. Emile Blanchard. These remarks are made in connection 

 with a collection of insects made in the delta of the Red River 

 by M. Langue, and recently forwarded to the Paris Natural 

 History Museum. It comprises 567 species of Coleopterae, 90 

 of LepidopterEE, and a few of Hemiptera;, Neuropter^, and 

 other orders. Most of them are common to the rest of Indo- 

 China, but several are new, either indigenous or related to 

 genera represented by more or less divergent species occurring 

 in other parts of the peninsula. This collection shows that on 

 the whole a considerable degree of uniformity characterises the 

 local fauna throughout all the coast-lands of Indo-China. — Note 

 on the specimen of rock brought by M. Lesseps from the hill at 

 Gamboa, on the line of the Panama Canal, by M. Fouque. 

 This specimen, picked up after the explosion by which the hill 

 was removed, is described as a microlithic volcanic rock, an 

 augitic labradorite with optical properties analogous to those 

 usually occurring in volcanic labr.adorites. — Remarks on the 

 rocks collected during the soundings of the Talisman, by 

 MM. Fouque and Michel Levy. Amongst these speci- 

 mens, mostly obtained from depths of from 4000 to 5000 

 metres, the older metamorphic is much more generally repre- 

 sented than the eruptive series. Sedimentary rocks also 

 occur in considerable abundance including 73 specimens of 

 limestones, 16 of arkoses, and 19 of sandstones, the latter 

 sometimes rich in remains of biotite and muscovite. — A first 

 experiment with an instrument intended to study the roll 

 of vessels at sea, by Admiral Paris. — Observations in con- 

 nection with M. Resal's recent note on the flexion of prisms, 

 by M. J. Boussinesq. The supposed error in M. de Saint- 

 Venant's theory of the flexion of prisms with elliptical base 

 is shown to be due to a mistake made by M. Resal himself 

 in his calculations. — Description of an automatic instrument 

 designed to register the heat liberated by living organisms (one 

 illustration), by M. A. d'Arsonval. By means of this extremely 

 sensitive "thermo-electric calorimeter" the physiologist is 

 enabled to determine and measure the quantity of heat liberated 

 hy cold-blooded animals, such as frogs and fishes, and even by 



